Topological Susceptibility and QCD Axion Mass: QED and NNLO corrections

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Autori principali: Gorghetto, Marco, Villadoro, Giovanni
Natura: Preprint
Pubblicazione: 2018
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author Gorghetto, Marco
Villadoro, Giovanni
author_facet Gorghetto, Marco
Villadoro, Giovanni
contents We improve the precision of the topological susceptibility of QCD, and therefore of the QCD axion mass, by including $O(α_{\rm em})$ and NNLO corrections in the chiral expansion, which amount to 0.65(21)% and -0.71(29)% respectively. Both corrections are one order of magnitude smaller than the known NLO ones, confirming the very good convergence of the chiral expansion and its reliability. Using the latest estimates for the light quark masses the current uncertainty is dominated by the one of the low-energy constant $\ell_7$. When combined with possible improvements on the light quark mass ratio and $\ell_7$ from lattice QCD, our computation could allow to determine the QCD axion mass with per-mille accuracy.
format Preprint
id arxiv_https___arxiv_org_abs_1812_01008
institution arXiv
publishDate 2018
record_format arxiv
spellingShingle Topological Susceptibility and QCD Axion Mass: QED and NNLO corrections
Gorghetto, Marco
Villadoro, Giovanni
High Energy Physics - Phenomenology
High Energy Physics - Lattice
We improve the precision of the topological susceptibility of QCD, and therefore of the QCD axion mass, by including $O(α_{\rm em})$ and NNLO corrections in the chiral expansion, which amount to 0.65(21)% and -0.71(29)% respectively. Both corrections are one order of magnitude smaller than the known NLO ones, confirming the very good convergence of the chiral expansion and its reliability. Using the latest estimates for the light quark masses the current uncertainty is dominated by the one of the low-energy constant $\ell_7$. When combined with possible improvements on the light quark mass ratio and $\ell_7$ from lattice QCD, our computation could allow to determine the QCD axion mass with per-mille accuracy.
title Topological Susceptibility and QCD Axion Mass: QED and NNLO corrections
topic High Energy Physics - Phenomenology
High Energy Physics - Lattice
url https://arxiv.org/abs/1812.01008